Base Sheet with Surface Fiber Structure

ABSTRACT

A base sheet formed from a nonwoven web and having a microstructured topography is provided. A plurality of staple fibers modified with a cation are affixed to the nonwoven web via an adhesive modified with an anion in order to improve one or more attributes of the nonwoven web, such as softness, absorption, abrasion, and barrier properties. The present disclosure also provides a method of forming a base sheet which includes printing the adhesive on the nonwoven web, and passing the nonwoven web through an electroplating module.

BACKGROUND

Conventional absorbent articles, including wiping products have beenmade from woven and knitted fabrics. Such wipers have been used in alldifferent types of industries, such as for industrial applications, foodservice applications, health and medical applications, and for generalconsumer use. Conventional rags and washcloths can be reusable iflaundered properly. Disposable wipers, however, continue to gain inpopularity and are readily displacing many conventional woven or knittedproducts. Disposable wipers, for instance, can offer many advantages.For example, disposable wipers are generally more sterile, as they aregenerally free of debris and contaminants, and can also be pre-loadedwith a cleaning solvent. Laundered rags and washcloths, for instance,can still contain residual debris from past use and can also pick updebris during the laundering process. In addition, laundering woven orknitted wipers can not only create a great expense, but also requiresthe use of copious amounts of water and detergents that must be properlydisposed of. Further, laundered rags and dishcloths require separatesolvents or surfactants to be kept on hand, as they cannot be pre-loadedunlike disposable wipers.

However, disposable wipers are often limited by conflicting interests.For instance, industrial wipers, food service wiping products, householdcleaning wipers, medical wiping products, and the like generally needgreater amounts of strength and should be capable of absorbing not onlywater-based solutions but also oily substances. Historically, however,problems have been encountered in producing such wipers that have bothgood water absorbency properties and good oil absorbency properties. Forexample, increasing the oil affinity of a wiping product may result in amore hydrophobic sheet that is less water absorbent. Similarly,increasing the water affinity of a wiping product may result in ahydrophilic sheet that has decreased oil absorbency. Additionally,providing a wiping product with good abrasiveness, for example, canlimit the softness and overall absorbance of the wiper. Similarly,barrier fabrics, such as those used in masks and performance fabricssuffer from conflicting interests. For instance, treating the barrierfabric to have improved barrier properties can also increase theabrasiveness of the fabric, providing discomfort when the fabriccontacted the skin of a user.

Further, altering the characteristics of these articles requiresaltering the composition used to form the base of the article, such as,by changing the fibers or other components used during formation of theunderlying nonwoven web. This can cause further problems, as any changeto the base composition can cause tradeoffs as discussed above, causedelays and difficulties during manufacturing, as well as be limited bythe underlying properties of the material.

Therefore, in one aspect, it would be beneficial to provide a base sheetthat has overall improved performance. For instance, in one aspect, itwould be beneficial to provide a base sheet that exhibits improvedperformance in one or more of softness, absorption, abrasion, andbarrier properties. Furthermore, it would be beneficial to provide anarticle formed from a base sheet that exhibits improved properties onopposed sides of the article.

SUMMARY

In one aspect, the present disclosure is generally directed to a basesheet having a microstructured topography. The base sheet includes anonwoven web having a first surface and an opposed second surface, andextends in a first plane. The base sheet further includes an adhesive,and a plurality of staple fibers that extend in one or more secondplanes that are not parallel to the first plane, that are affixed to thefirst surface of the nonwoven web by the adhesive. Furthermore, at leasta portion of the staple fibers have a length of about 5000 micrometersor less, a denier of about 5 or less, or a combination thereof.

In a further aspect, the base sheet is a wiping product or an absorbentarticle. Furthermore, in an aspect, at least a portion of the staplefibers have a length of about 1500 micrometers or less and a denier ofabout 3 or less, or a length of about 1500 micrometers to about 5000micrometers, and a denier of about 3 to about 5.

Moreover, in an aspect, the nonwoven web includes elastomeric fibers,three-dimensional fibers, debonded cellulosic fibers, pulp fibers, ormixtures thereof. Additionally or alternatively, the nonwoven webincludes polyethylene fibers, polyethylene fibers, pulp fibers, or acombination thereof. In a further aspect, the nonwoven web is a spunbondnonwoven web. Furthermore, in one aspect, the nonwoven web is embossed

In yet another aspect, the plurality of staple fibers includepolyethylene fibers, polypropylene fibers, rayon fibers, nylon fibers,or a combination thereof. Furthermore, in an aspect, the adhesiveincludes an anionic component, the plurality of staple fibers contain acation, or a combination thereof. In one aspect, the anionic componentand adhesive are coated on at least a portion of the nonwoven web.Additionally or alternatively, 50% or more of the nonwoven web is coatedwith the anionic component and adhesive. In one aspect, the anioniccomponent and adhesive are applied on the nonwoven web in a pattern thatincludes circles, squares, lines, or a combination thereof. Moreover, inan aspect, the base sheet includes a second plurality of staple fibersadhered to the second surface of the nonwoven web by an adhesive. In anaspect, the second plurality of staple fibers have a different length,denier, or fiber composition than the first plurality of staple fibers,or a combination thereof.

Furthermore, in one aspect, the nonwoven web exhibits: a water capacityof about 200% to about 800%, a cup crush load of less than about 100grams, when measured using a 34 gsm nonwoven web, a bacterial filtrationefficiency of about 80% or greater, or a combination thereof. In anaspect, the base sheet exhibits a 10% or greater improvement in one ormore of water capacity, cup crush load, or bacterial filtration, ascompared to the same nonwoven web that does not include the plurality ofstaple fibers

The present disclosure is also generally directed to a method of forminga base sheet. The method includes forming a nonwoven web that extends ina first plane, applying an adhesive to a first surface of the nonwovenweb, and adhering a plurality of staple fibers to the nonwoven web. Insuch an aspect, at least a portion of the plurality of staple fibersextend in one or more second planes that are not parallel to the firstplane, and have a length of 5000 micrometers or less, a denier of 5 orless, or a combination thereof.

In another aspect, the adhesive includes an anionic component, where theanionic component and the adhesive are printed on the nonwoven web. Inyet a further aspect, the anionic component and the adhesive areflexographically printed onto the nonwoven web and the plurality ofstaple fibers are electrostatically adhered to the nonwoven web.Additionally or alternatively, the base sheet is calendared.

Other features and aspects of the present disclosure are discussed ingreater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present disclosure is set forthmore particularly in the remainder of the specification, includingreference to the accompanying figures, in which:

FIG. 1 illustrates a cross-sectional view of an aspect of a base sheetaccording to the present disclosure;

FIG. 2 illustrates a cross-sectional view of an aspect of a base sheetaccording to the present disclosure; and

FIG. 3 illustrates a method of forming a base sheet according to thepresent disclosure.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

Definitions

The terms “about,” “approximately,” or “generally,”, when used herein tomodify a value, indicates that the value can be raised or lowered by10%, such as 7.5%, such as 5%, such as 4%, such as 3%, such as 2%, orsuch as 1%, and remain within the disclosed aspect.

The term “fiber” as used herein refers to an elongate particulate havingan apparent length greatly exceeding its apparent width, i.e. a lengthto diameter ratio of at least about 10. More specifically, as usedherein, fiber refers to papermaking fibers. The present inventioncontemplates the use of a variety of papermaking fibers, such as, forexample, natural fibers or synthetic fibers, or any other suitablefibers, and any combination thereof. Papermaking fibers useful in thepresent invention include cellulosic fibers commonly and moreparticularly wood pulp fibers.

The term “nonwoven web” generally refers to a web having a structure ofindividual fibers or threads which are interlaid, but not in anidentifiable manner as in a knitted fabric. Examples of suitablenonwoven fabrics or webs include, but are not limited to, meltblownwebs, spunbond webs, bonded carded webs, airlaid webs, coform webs,hydraulically entangled webs, and so forth.

The term “meltblown web” generally refers to a nonwoven web that isformed by a process in which a molten thermoplastic material is extrudedthrough a plurality of fine, usually circular, die capillaries as moltenfibers into converging high velocity gas (e.g., air) streams thatattenuate the fibers of molten thermoplastic material to reduce theirdiameter, which may be to microfiber diameter. Thereafter, the meltblownfibers are carried by the high velocity gas stream and are deposited ona collecting surface to form a web of randomly dispersed meltblownfibers. Such a process is disclosed, for example, in U.S. Pat. No.3,849,241 to Butin, et al., which is incorporated herein in its entiretyby reference thereto for all purposes. Generally speaking, meltblownfibers may be microfibers that are substantially continuous ordiscontinuous, generally smaller than 10 microns in diameter, andgenerally tacky when deposited onto a collecting surface.

The term “spunbond web” generally refers to a web containing smalldiameter substantially continuous fibers. The fibers are formed byextruding a molten thermoplastic material from a plurality of fine,usually circular, capillaries of a spinnerette with the diameter of theextruded fibers then being rapidly reduced as by, for example, eductivedrawing and/or other well-known spunbonding mechanisms. The productionof spunbond webs is described and illustrated, for example, in U.S. Pat.No. 4,340,563 to Appel, et al., U.S. Pat. No. 3,692,618 to Dorschner, etal., U.S. Pat. No. 3,802,817 to Matsuki, et al., U.S. Pat. No. 3,338,992to Kinney, U.S. Pat. No. 3,341,394 to Kinney, U.S. Pat. No. 3,502,763 toHartman, U.S. Pat. No. 3,502,538 to Levy, U.S. Pat. No. 3,542,615 toDobo, et al., and U.S. Pat. No. 5,382,400 to Pike, et al., which areincorporated herein in their entirety by reference thereto for allpurposes. Spunbond fibers are generally not tacky when they aredeposited onto a collecting surface. Spunbond fibers may sometimes havediameters less than about 40 microns, and are often between about 5 toabout 20 microns.

The term “coform” generally refers to composite materials comprising amixture or stabilized matrix of thermoplastic fibers and a secondnon-thermoplastic material. As an example, coform materials may be madeby a process in which at least one meltblown die head is arranged near achute through which other materials are added to the web while it isforming. Such other materials may include, but are not limited to,fibrous organic materials such as woody or non-woody pulp such ascotton, rayon, recycled paper, pulp fluff and also superabsorbentparticles, inorganic and/or organic absorbent materials, treatedpolymeric staple fibers and so forth. Some examples of such coformmaterials are disclosed in U.S. Pat. No. 4,100,324 to Anderson, et al.,U.S. Pat. No. 5,284,703 to Everhart, et al., and U.S. Pat. No. 5,350,624to Georger, et al., each of which are incorporated herein in theirentirety by reference thereto for all purposes.

The term “bonded carded web” refers to webs made from staple fiberswhich are sent through a combing or carding unit, which breaks apart andaligns the staple fibers in the machine direction to form a generallymachine direction-oriented fibrous nonwoven web. Such fibers are usuallypurchased in bales which are placed in a picker or fiberizer whichseparates the fibers prior to the carding unit. Once the web is formed,it is then bonded by one or more of several known bonding methods.

The term “elastomeric” and “elastic” and refers to a material that, uponapplication of a stretching force, is stretchable in at least onedirection (such as the CD direction), and which upon release of thestretching force, contracts/returns to approximately its originaldimension. For example, a stretched material may have a stretched lengththat is at least 50% greater than its relaxed unstretched length, andwhich will recover to within at least 50% of its stretched length uponrelease of the stretching force. A hypothetical example would be a one(1) inch sample of a material that is stretchable to at least 1.50inches and which, upon release of the stretching force, will recover toa length of not more than 1.25 inches. Desirably, the material contractsor recovers at least 50%, and even more desirably, at least 80% of thestretched length.

The term “thermal point bonding” generally refers to a processperformed, for example, by passing a material between a patterned roll(e.g., calender roll) and another roll (e.g., anvil roll), which may ormay not be patterned. One or both of the rolls are typically heated.

The term “ultrasonic bonding” generally refers to a process performed,for example, by passing a material between a sonic horn and a patternedroll (e.g., anvil roll). For instance, ultrasonic bonding through theuse of a stationary horn and a rotating patterned anvil roll isdescribed in U.S. Pat. No. 3,939,033 to Grgach, et al., U.S. Pat. No.3,844,869 to Rust Jr., and U.S. Pat. No. 4,259,399 to Hill, which areincorporated herein in their entirety by reference thereto for allpurposes. Moreover, ultrasonic bonding through the use of a rotary hornwith a rotating patterned anvil roll is described in U.S. Pat. No.5,096,532 to Neuwirth, et al., U.S. Pat. No. 5,110,403 to Ehlert, andU.S. Pat. No. 5,817,199 to Brennecke, et al., which are incorporatedherein in their entirety by reference thereto for all purposes. Ofcourse, any other ultrasonic bonding technique may also be used in thepresent invention.

The term “slurry” as used herein refers to a mixture comprising fibersand water.

The term “absorbent article” or “article” when used herein refers toproducts made from fibrous webs which includes, but is not limited to,personal care absorbent articles, such as baby wipes, mitt wipes,diapers, pant diapers, open diapers, training pants, absorbentunderpants, incontinence articles, feminine hygiene products (e.g.,sanitary napkins), swim wear and so forth; medical absorbent articles,such as garments, fenestration materials, underpads, bedpads, bandages,absorbent drapes, and medical wipes; food service wipers; clothingarticles; pouches, and so forth. Materials and processes suitable forforming such articles are well known to those skilled in the art. Anabsorbent article, for example, can include a liner, an outer cover, andan absorbent material or pad formed from a fibrous web positionedtherebetween.

The term “wiping product” as used herein refers to products made fromfibrous webs and includes paper towels, industrial wipers, foodservicewipers, napkins, medical pads, and other similar products. It should beunderstood that, in one aspect, a wiping product may be included whenreferring to an absorbent article or absorbent web according to thepresent disclosure.

As used herein, the term “basis weight” generally refers to the dryweight per unit area of a fibrous product and is generally expressed asgrams per square meter (gsm). Basis weight is measured using TAPPI testmethod T-220.

The term “machine direction” as used herein refers to the direction oftravel of the forming surface onto which fibers are deposited duringformation of a nonwoven web.

The term “cross-machine direction” as used herein refers to thedirection which is perpendicular to the machine direction defined aboveand in the plane of the forming surface.

The term “pulp” as used herein refers to fibers from natural sourcessuch as woody and non-woody plants. Woody plants include, for example,deciduous and coniferous trees. Non-woody plants include, for example,cotton, flax, esparto grass, milkweed, straw, jute, hemp, and bagasse.Pulp fibers can include hardwood fibers, softwood fibers, and mixturesthereof.

The term “average fiber length” as used herein refers to an averagelength of fibers, fiber bundles and/or fiber-like materials determinedby measurement utilizing microscopic techniques. A sample of at least 20randomly selected fibers is separated from a liquid suspension offibers. The fibers are set up on a microscope slide prepared to suspendthe fibers in water. A tinting dye is added to the suspended fibers tocolor cellulose-containing fibers so they may be distinguished orseparated from synthetic fibers. The slide is placed under a FisherStereomaster II Microscope—S19642/S19643 Series. Measurements of 20fibers in the sample are made at 20× linear magnification utilizing a0-20 mils scale and an average length, minimum and maximum length, and adeviation or coefficient of variation are calculated. In some cases, theaverage fiber length will be calculated as a weighted average length offibers (e.g., fibers, fiber bundles, fiber-like materials) determined byequipment such as, for example, a Kajaani fiber analyzer Model No.FS-200, available from Kajaani Oy Electronics, Kajaani, Finland.According to a standard test procedure, a sample is treated with amacerating liquid to ensure that no fiber bundles or shives are present.Each sample is disintegrated into hot water and diluted to anapproximately 0.001% suspension. Individual test samples are drawn inapproximately 50 to 100 ml portions from the dilute suspension whentested using the standard Kajaani fiber analysis test procedure. Theweighted average fiber length may be an arithmetic average, a lengthweighted average or a weight weighted average and may be expressed bythe following equation:

$\sum\limits_{x_{i} = 0}^{k}{\left( {x_{i}*n_{i}} \right)/n}$

where

-   -   k=maximum fiber length    -   x_(i)=fiber length    -   n_(i)=number of fibers having length xi    -   n=total number of fibers measured.

One characteristic of the average fiber length data measured by theKajaani fiber analyzer is that it does not discriminate betweendifferent types of fibers. Thus, the average length represents anaverage based on lengths of all different types, if any, of fibers inthe sample.

The term “staple fibers” means discontinuous fibers made from syntheticpolymers such as polypropylene, polyester, post consumer recycle (PCR)fibers, polyester, nylon, and the like, and those not hydrophilic may betreated to be hydrophilic. Staple fibers may be cut fibers or the like.Staple fibers can have cross-sections that are round, bicomponent,multicomponent, shaped, hollow, or the like.

As used herein, the term “abrasive” is intended to represent a surfacetexture which enables the nonwoven web to scour a surface being wiped orcleaned with the nonwoven web and remove dirt and the like. Theabrasiveness can vary depending on the polymer used to prepare theabrasive fibers and the degree of texture of the nonwoven web.

DETAILED DESCRIPTION

It is to be understood by one of ordinary skill in the art that thepresent discussion is a description of exemplary aspects only, and isnot intended as limiting the broader aspects of the present disclosure.

Generally speaking, the present disclosure is directed to a base sheethaving a microstructured topography that is formed from a nonwoven weband at least a first plurality of staple fibers adhered to a first sideof the nonwoven web. Particularly, the present disclosure has found thatby carefully selecting staple fibers and adhering the staple fibers tothe nonwoven web such that the staple fibers extend in a directiongenerally non-planar with the nonwoven web, one or more properties ofthe base sheet can be improved without impacting the properties of thenonwoven web, and without the need for altering the composition of thenonwoven web. Furthermore, in one aspect, the present disclosure hasfound that a second plurality of staple fibers can be adhered to asecond side of the nonwoven web. In such an aspect, the second pluralityof staple fibers can be different in size, shape, or properties (such aswater absorbency, oil absorbency, etc) than the first plurality offibers, providing the base sheet with different properties on each ofits surfaces, without requiring change in composition or treatment ofthe nonwoven web.

For instance, in one aspect, the first and/or second plurality of staplefibers may be selected to improve one or more properties of the nonwovenweb, such as water absorbency, oil absorbency, softness, abrasiveness,durability, barrier properties or the like. For instance, a staple fibermay be selected based upon the material's ability to improve theseproperties, and can be formed from one or more synthetic fibers. In oneaspect, the staple fiber(s) can be formed from polypropylene, polyester,post consumer recycle (PCR) fibers, pre-consumer (e.g. post industrial)recycle fibers, rayon, polyester, nylon, and the like. In one aspect,the fibers can be formed from polypropylene, polyester, rayon, nylon, ora combination thereof. While a fiber inherently have one or more of theabove properties may be selected, it should be understood that, in oneaspect, the fiber(s) selected may be treated to impart, or increasetheir hydrophobicity, absorbency, or others as known in the art.However, in one aspect, the staple fibers can also include cellulosicfibers, such as cotton, including fibers from waste and recycling,including agro-industrial and textile waste.

Nonetheless, in one aspect, one or more of the above materials may beused to form the staple fibers, and the length and/or denier of thefiber may be altered to impart further advantages. For instance, shorterand/or thinner (e.g. lower denier) fibers can provide a softer surfacewhereas longer and/or thicker (e.g. higher denier) fibers can improveabrasiveness or durability. Thus, in one aspect, the first and/or secondplurality of staple fibers can have a denier of about 20 or less, suchas about 17.5 or less, such as about 15 or less, such as about 12.5 orless, such as about 10 or less, such as about 8 or less, such as about 6or less, such as about 5 or less, such as about 4 or less, such as about3 or less, such as about 2 or less, or any ranges or valuestherebetween.

Furthermore, additionally or alternatively, the fibers may have alength, which is the staple fiber's longest dimension, of about 10micrometers to about 5000 micrometers, such as about 50 micrometers toabout 4000 micrometers, such as about 100 micrometers to about 3000micrometers, such as about 150 micrometers to about 2000 micrometers,such as about 200 micrometers to about 1000 micrometers, such as about250 micrometers to about 750 micrometers, or any ranges or valuestherebetween.

Furthermore, in one aspect, a staple fiber providing softness may have adenier of about 4 or less, such as about 3.5 or less, such as about 3 orless, such as about 2.5 or less, such as about 2 or less, such as about1.5 or less, such as about 1 or less, such as about 0.9 or less, such asabout 0.8 or less, or any ranges or values therebetween, and/or a lengthof about 2000 micrometers or less, such as about 1750 micrometers orless, such as about 1500 micrometers or less, such as about 1000micrometers or less, such as about 500 micrometers or less. Forinstance, in one aspect, soft fibers have a denier of about 2.5 to about3.5 and a length of about 1000 micrometers to about 1700 micrometers, adenier of about 1 to about 2 and a length of about 500 micrometers toabout 1500 micrometers, a denier of about 0.5 to about 1, and a lengthof about 250 micrometers to about 1000 micrometers, or any ranges orvalues therebetween.

Similarly, a fiber having good abrasiveness or wear properties may havea denier of about 4 or greater, such as about 5 or greater, such asabout 7.5 or greater, such as about 10 or greater, such as about 15 orgreater, such as about 20 or greater, such as about 25 or greater, suchas about 30 or greater, such as about 35 or greater, such as about 45 orless, such as about 40 or less, such as about 35 or less, such as about30 or less, such as about 25 or less, or any ranges or valuestherebetween, and/or a length of about 10 millimeters or less, such asabout 9 millimeters or less, such as about 8 millimeters or less, suchas about 7 millimeters or less, such as about 6000 micrometers or less,such as about 5000 micrometers or less, such as about 4000 micrometersor less, such as about 3000 micrometers or less, such as about 2000micrometers or less, such as about 1200 micrometers or greater, such asabout 1300 micrometers or greater, such as about 1400 micrometers orgreater, such as about 1500 micrometers or greater, or any values orranges therebetween. For instance, in one aspect, an abrasive fiber hasa denier of about 5 to about 7 and a length of about 1250 micrometers toabout 4000 micrometers, a denier of about 9.5 to about 12 and a lengthof about 2500 micrometers to about 5500 micrometers, a denier of about19 to about 21 and a length of about 4500 micrometers to about 7500micrometers, a denier of about 38 to about 41 and a length of about 6500micrometers to about 10,000 micrometers, or any ranges or valuestherebetween.

Regardless of the type and size of fibers selected, the fibers aretreated with a cation. In one aspect, the cation is incorporated duringformation of the staple fibers, however, it should be understood thatthe cation can be incorporated into the staple fibers after formation,such as by treating the staple fibers. In one aspect, the cation is ametal cation, such as an alkali metal cation, and, in one aspect, may beselected from potassium, sodium, lithium, or a combination thereof. Inone aspect, a suitable cationically charged fibers can be obtained astreated staple fibers from Agatex.

Particularly, in one aspect, as discussed above, the plurality of fibersare attached to the nonwoven web via an adhesive after being exposed toa magnetic field. As will be discussed in greater detail below, theadhesive can be applied to the nonwoven web using a variety oftechniques, including printing, spraying, dipping, and the like.Nonetheless, in one aspect, the adhesive may be any adhesive known inthe art, but may be treated with an anion. Thus, as will be discussed ingreater detail below, the plurality of fibers may be plated or depositedon the nonwoven web due to the attraction between the cationincorporated into or onto the fibers, and the anionic componentincorporated into the adhesive. While any anion known in the art may beused, in one aspect, the anion is an anion with suitable attraction to ametal cation, such as an alkali metal cation. Thus, in one aspect, theanion can include a mineral anion, such as chlorine, bromine, iodine, ora fluorinated salt anion, such as PF₆ ⁻, SCN⁻, ClO₄ ⁻, CF₃SO₃ ⁻,(FSO₂)₂N⁻, (CF₃SO₂)₂N⁻, (C₂F₆SO₂)₂N⁻, and (CF₃SO₂)₃C⁻, or a combinationthereof. In one aspect, a suitable anionically treated adhesive can beobtained from Agatex.

Notwithstanding the adhesive selected, in one aspect, the fibers areadhered to one or more surfaces of the nonwoven web via the adhesive.For instance, referring to FIG. 1 , a nonwoven web 102 can have anadhesive 104 applied thereon, and a first plurality of staple fibers 106affixed to the nonwoven web via the adhesive to form a base web 100having a microstructured topography. Moreover, referring to FIG. 2 , andas discussed above, in one aspect, the first plurality of staple fibersare affixed to a first side 108 of the nonwoven web, and a secondplurality of staple fibers 114 are affixed to a second side 110 of thenonwoven web 102 via adhesive 112. In one aspect, the first plurality ofstaple fibers 106 may be the same or different than the second pluralityof staple fibers 114 as discussed above. Similarly, in one aspect, theadhesive 112 may be the same or different than adhesive 104. Forinstance, in one aspect, the adhesive itself may be generally the sameor similar, but adhesive 104 may be treated with a different anion thatadhesive 112. However, in one aspect, adhesive 104 is the same, orgenerally the same, as adhesive 112.

Further, while the adhesive 104 and/or 112 is shown in FIGS. 1 and 2 ascovering the entire nonwoven web 102, it should be understood that, insome aspects, that the adhesive may be applied to about 50% or more ofthe nonwoven web, such as about 60% or more, such as about 70% or more,such as about 75% or more such as about 80% or more, such as about 85%or more, such as about 90% or more, such as about 95% or more, such asabout 100% or less, such as about 99% or less, such as about 95% orless, such as about 90% or less, such as about 85% or less, such as about 80% or less of the first and/or second surface of the nonwoven web,or any ranges or values therebetween. Thus, in one aspect, the adhesivemay be applied in a pattern, such as dots, squares, lines, and the like.

Nonetheless, as shown in FIGS. 1 and 2 , the first and/or secondplurality of staple fibers 106/114 extend along their length (e.g.largest dimension from the surface of the nonwoven web to a distal endof the staple fiber) in one or more planes which are not planar with orparallel to nonwoven web 102. Particularly, as shown, in one aspect, andfor example only, nonwoven web 102 extends in a generally horizontaldirection along the x-axis, whereas staple fibers 106/116 extend in avariety of second planes that are not planar with, or parallel to thex-axis, forming a microstructured topography on the first and/or secondsurface of the nonwoven web. It should be understood that, due to theprocess of attaching the fibers, which will be discussed in greaterdetail below, some staple fibers 106/114 may become attached such thatthe length extends generally parallel to nonwoven web 102, however, atleast a portion, such as about 50% or more, such as about 60% or more,such as about 70% or more, such as about 75% or more, such as about 80%or more, of the fibers may extend in one or more second planes that arenot planar with or parallel to the first plane in which nonwoven web 102extends. Thus, the first or second plurality of staple fibers arefurther distinguished from an outer layer in a laminate or layerednonwoven configuration.

Furthermore, the present disclosure has surprisingly found that theplurality of staple fibers do not diminish the underlying properties ofthe base web, and can, in fact, increase one or more of absorbency,abrasiveness, softness, barrier properties or the like.

For instance, in one aspect, the nonwoven web may be capable ofabsorbing between 3.5 and 6.0 grams of water per gram of nonwoven web.In certain exemplary aspects, the water capacity of the nonwoven web,determined by measuring the increase in the weight of a material sampleresulting from the absorption of a liquid, may be between about 200% toabout 800%, such as about 250% to about 750%, such as about 300% toabout 700%, such as about 350% to about 600%, or any ranges or valuestherebetween. Further, the nonwoven web may be capable of absorbingbetween 3.7 and 4.3 grams of water in an amount of time between about 1second and about 2 seconds, such as about 1.1 seconds to about 1.9seconds, such as about 1.2 seconds to about 1.8 seconds, such as about1.25 to about 1.6 second, or any ranges or values therebetween.Moreover, as discussed above, it was unexpectedly found that by formingthe base sheet according to the present disclosure, the properties ofthe nonwoven web may be maintained at the above levels, or evenincreased if a fiber improving absorbency is selected.

In one aspect, the nonwoven web may also exhibit good barrierproperties, and may filter at least about 70% or more of airborneparticles having a size of about 0.65 microns or greater according to EN13274-7 (utilizing a Sodium Chloride aerosol have a particle size of0.65 microns and a velocity of 95 liters/minute over an area of 100 cm),such as about 75% or more, such as about 80% or more, such as about 85%or more, such as about 90% or more of particles having a size of about0.65 microns or greater. Similarly, these barrier properties may beexhibited while maintaining good air permeability through the nonwovenweb. For instance, the nonwoven web can exhibit an air permeabilitymeasured according to ASTM D737 (2020, measured using a 38 cm² sampleand a pressure of 125 Pa) of about 20 cfm or greater, such as about 25cfm or greater, such as about 30 cfm or greater, such as about 32.5 cfmor greater, such as about 35 cfm or greater, such as about 40 cfm orgreater, or any ranges or values therebetween. Additionally oralternatively, the nonwoven web may exhibit a bacterial filtrationefficiency (BCE), the test for which is defined below, of about 80% orgreater, such as about 85% or greater, such as about 90% or greater,such as about 95% or greater.

The nonwoven web may also have softness measured as cup crush energy, ofless than about 1500 gm-mm, such as about 1400 gm-mm or less, such asabout 1300 gm-mm or less, such as about 1200 gm-mm or less, and cupcrush load of less than about 100 grams, such as about 95 grams, such asabout 90 grams, such as about 85 grams, such as about 80 grams, such asabout 75 grams, such as about 70 grams, when testing a 34 gsm webaccording to the cup crush test set forth below.

Furthermore, the present disclosure has found that these properties canbe maintained or even improved by incorporating staple fibers accordingto the present disclosure. For instance, one or more of the aboveproperties may be improved by about 10% of the above values or more,such as about 20%, such as about 30%, such as about 40%, such as about50% or more based upon the fiber, denier, and length selected.Furthermore, in one aspect, a property that is not inherent to thenonwoven web may be imparted to the nonwoven web/base sheet byincorporating a fiber having one or more of the above properties withoutimpacting (e.g. decreasing or reducing) the above discussed propertiesof the nonwoven web. For instance, a nonwoven web having barrierproperties according to the above may be combined with fibers havinghigh softness, improving the softness of the barrier fabric withoutimpacting the barrier properties. In such an aspect, the base sheet mayhave a softness that is 10% or greater than the same nonwoven web havingbarrier properties that has not been treated with a plurality of staplefibers, such as about 15% or greater, such as about 20% or greater, suchas about 25% or greater. Similarly, in one aspect, an absorbent nonwovenweb may be treated with abrasive fibers which increase the abrasivenessby about 10% or more than the same absorbent nonwoven web that has notbeen treated with a plurality of staple fibers, such as about 15% orgreater, such as about 20% or greater, such as about 25% or greater.Moreover, in one aspect, a nonwoven web having water or oil absorbencymay contain a plurality of fibers to improve the other of water or oilabsorbency, such that a first side of the nonwoven web may be oilabsorbent and the opposite be water absorbent. For instance, theabsorbent nonwoven web may be treated with oil or water absorbent fiberswhich increase the respective absorbency by about 10% or more than thesame absorbent nonwoven web that has not been treated with a pluralityof staple fibers, such as about 15% or greater, such as about 20% orgreater, such as about 25% or greater. Of course, as noted above, itshould be understood that a first plurality of fibers may be adhered toa first side of the nonwoven wed, and a second plurality may be adheredto a second side of the nonwoven web, such that two or more of the aboveproperties may be improved while maintaining, if not improving, theproperties of the nonwoven web.

The nonwoven web may be formed from one or more of a variety of polymersthat can be used in forming the nonwoven web material can includeolefins (e.g., polyethylenes and polypropylenes), polyesters (e.g.,polybutylene terephthalate, polybutylene naphthalate), polyamides (e.g.,nylons), polycarbonates, polyphenylene sulfides, polystyrenes,polyurethanes (e.g., thermoplastic polyurethanes), etc. In oneparticular embodiment, the fibers of the nonwoven web material caninclude an olefin homopolymer. One suitable olefin homopolymer is apropylene homopolymer having a density of 0.91 grams per cubiccentimeter (g/cm³), a melt flow rate of 1200 g/10 minute (230° C., 2.16kg), a crystallization temperature of 113° C., and a melting temperatureof 156° C., and is available as METOCENE MF650X polymer fromLyondellBasell Industries in Rotterdam, The Netherlands. Anothersuitable propylene homopolymer that can be used has a density of 0.905g/cm³, a melt flow rate of 1300 g/10 minute (230° C., 2.16 kg), and amelting temperature of 165° C., and is available as Polypropylene 3962from Total Petrochemicals in Houston, Texas. Another suitablepolypropylene is available as EXXTRAL™ 3155, available from ExxonMobilChemical Company of Houston, Texas.

Further, a variety of thermoplastic elastomeric and plastomeric polymersmay generally be employed in the nonwoven web material of the presentinvention, such as elastomeric polyesters, elastomeric polyurethanes,elastomeric polyamides, elastomeric copolymers, elastomeric polyolefins,and so forth. In one particular embodiment, elastomeric semi-crystallinepolyolefins are employed due to their unique combination of mechanicaland elastomeric properties. Semi-crystalline polyolefins have or arecapable of exhibiting a substantially regular structure. For example,semi-crystalline polyolefins may be substantially amorphous in theirundeformed state, but form crystalline domains upon stretching. Thedegree of crystallinity of the olefin polymer may be from about 3% toabout 60%, in some embodiments from about 5% to about 45%, in someembodiments from about 5% to about 30%, and in some embodiments, fromabout 5% and about 15%. Likewise, the semi-crystalline polyolefin mayhave a latent heat of fusion (ΔH_(f)), which is another indicator of thedegree of crystallinity, of from about 15 to about 210 Joules per gram(“J/g”), in some embodiments from about to about 100 J/g, in someembodiments from about 20 to about 65 J/g, and in some embodiments, from25 to about 50 J/g. The semi-crystalline polyolefin may also have aVicat softening temperature of from about 10° C. to about 100° C., insome embodiments from about 20° C. to about 80° C., and in someembodiments, from about 30° C. to about 60° C. The semi-crystallinepolyolefin may have a melting temperature of from about 20° C. to about120° C., in some embodiments from about 35° C. to about 90° C., and insome embodiments, from about 40° C. to about 80° C. The latent heat offusion (ΔH_(f)) and melting temperature may be determined usingdifferential scanning calorimetry (“DSC”) in accordance with ASTM D-3417as is well known to those skilled in the art. The Vicat softeningtemperature may be determined in accordance with ASTM D-1525.

Exemplary semi-crystalline polyolefins include polyethylene,polypropylene, as well as their blends and copolymers thereof. In oneparticular embodiment, a polyethylene is employed that is a copolymer ofethylene and an α-olefin, such as a C₃-C₂₀ α-olefin or C₃-C₁₂ α-olefin.Suitable α-olefins may be linear or branched (e.g., one or more C₁-C₃alkyl branches, or an aryl group). Specific examples include 1-butene;3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene; 1-pentene with oneor more methyl, ethyl or propyl substituents; 1-hexene with one or moremethyl, ethyl or propyl substituents; 1-heptene with one or more methyl,ethyl or propyl substituents; 1-octene with one or more methyl, ethyl orpropyl substituents; 1-nonene with one or more methyl, ethyl or propylsubstituents; ethyl, methyl or dimethyl-substituted 1-decene;1-dodecene; and styrene. Particularly desired α-olefin comonomers are1-butene, 1-hexene, and 1-octene. The ethylene content of suchcopolymers may be from about 60 mole % to about 99 mole %, in someembodiments from about 80 mole % to about 98.5 mole %, and in someembodiments, from about 87 mole % to about 97.5 mole %. The α-olefincontent may likewise range from about 1 mole % to about 40 mole %, insome embodiments from about 1.5 mole % to about 15 mole %, and in someembodiments, from about 2.5 mole % to about 13 mole %.

The density of the polyethylene may vary depending on the type ofpolymer employed, but generally ranges from about 0.85 g/cm³ to about0.96 g/cm³. Polyethylene “plastomers”, for instance, may have a densityin the range of from 0.85 g/cm³ to 0.91 g/cm³. Likewise, “linear lowdensity polyethylene” (“LLDPE”) may have a density in the range of fromabout 0.91 g/cm³ to about 0.94 g/cm³; “low density polyethylene”(“LDPE”) may have a density in the range of from about 0.91 g/cm³ toabout 0.94 g/cm³; and “high density polyethylene” (“HDPE”) may havedensity in the range of from g/cm³ to 0.96 g/cm³. Densities may bemeasured in accordance with ASTM 1505.

Particularly suitable polyethylene copolymers are those that are“linear” or “substantially linear.” The term “substantially linear”means that, in addition to the short chain branches attributable tocomonomer incorporation, the ethylene polymer also contains long chainbranches in the polymer backbone. “Long chain branching” refers to achain length of at least 6 carbons. Each long chain branch may have thesame comonomer distribution as the polymer backbone and be as long asthe polymer backbone to which it is attached. Preferred substantiallylinear polymers are substituted with from 0.01 long chain branch per1000 carbons to 1 long chain branch per 1000 carbons, and in someembodiments, from 0.05 long chain branch per 1000 carbons to 1 longchain branch per 1000 carbons. In contrast to the term “substantiallylinear”, the term “linear” means that the polymer lacks measurable ordemonstrable long chain branches. That is, the polymer is substitutedwith an average of less than 0.01 long chain branch per 1000 carbons.

The density of a linear ethylene/α-olefin copolymer is a function ofboth the length and amount of the α-olefin. That is, the greater thelength of the α-olefin and the greater the amount of α-olefin present,the lower the density of the copolymer. Although not necessarilyrequired, linear polyethylene “plastomers” are particularly desirable inthat the content of α-olefin short chain branching content is such thatthe ethylene copolymer exhibits both plastic and elastomericcharacteristics—i.e., a “plastomer.” Because polymerization withα-olefin comonomers decreases crystallinity and density, the resultingplastomer normally has a density lower than that of polyethylenethermoplastic polymers (e.g., LLDPE), but approaching and/or overlappingthat of an elastomer. For example, the density of the polyethyleneplastomer may be 0.91 g/cm³ or less, in some embodiments, from about0.85 g/cm³ to about 0.88 g/cm³, and in some embodiments, from about 0.85g/cm³ to about 0.87 g/cm³. Despite having a density similar toelastomers, plastomers generally exhibit a higher degree ofcrystallinity and may be formed into pellets that are non-adhesive andrelatively free flowing.

The distribution of the α-olefin comonomer within a polyethyleneplastomer is typically random and uniform among the differing molecularweight fractions forming the ethylene copolymer. This uniformity ofcomonomer distribution within the plastomer may be expressed as acomonomer distribution breadth index value (“CDBI”) of 60 or more, insome embodiments 80 or more, and in some embodiments, 90 or more.Further, the polyethylene plastomer may be characterized by a DSCmelting point curve that exhibits the occurrence of a single meltingpoint peak occurring in the region of 50 to 110° C. (second meltrundown).

Preferred plastomers for use in the present invention are ethylene-basedcopolymer plastomers available under the designation EXACT™ fromExxonMobil Chemical Company of Houston, Texas. Other suitablepolyethylene-based plastomers are available under the designationENGAGE™ and AFFINITY™ from Dow Chemical Company of Midland, Michigan. Anadditional suitable polyethylene-based plastomer is an olefin blockcopolymer available from Dow Chemical Company of Midland, Michigan underthe trade designation INFUSE™, such as INFUSE™ 9807. A polyethylene thatcan be used in the fibers of the present invention is DOW™ 61800.41.Still other suitable ethylene polymers are available from The DowChemical Company under the designations DOWLEX™ (LLDPE), ASPUN™ (LLDPE),and ATTANE™ (ULDPE). Other suitable ethylene polymers are described inU.S. Pat. No. 4,937,299 to Ewen et al.; U.S. Pat. No. 5,218,071 toTsutsui et al.; U.S. Pat. No. 5,272,236 to Lai, et al.; and U.S. Pat.No. 5,278,272 to Lai, et al., which are incorporated herein in theirentirety by reference thereto for all purposes.

Of course, the present invention is by no means limited to the use ofethylene polymers. For instance, propylene polymers may also be suitablefor use as a semi-crystalline polyolefin. Suitable plastomeric propylenepolymers may include, for instance, copolymers or terpolymers ofpropylene include copolymers of propylene with an α-olefin (e.g.,C₃-C₂₀), such as ethylene, 1-butene, 2-butene, the various penteneisomers, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-unidecene,1-dodecene, 4-methyl-1-pentene, 4-methyl-1-hexene, 5-methyl-1-hexene,vinylcyclohexene, styrene, etc. The comonomer content of the propylenepolymer may be about 35 wt. % or less, in some embodiments from about 1wt. % to about 20 wt. %, and in some embodiments, from about 2 wt. % toabout 10 wt. %. Preferably, the density of the polypropylene (e.g.,propylene/α-olefin copolymer) may be 0.91 grams per cubic centimeter(g/cm³) or less, in some embodiments, from 0.85 to 0.88 g/cm³, and insome embodiments, from 0.85 g/cm³ to 0.87 g/cm³. Suitablepropylene-based copolymer plastomers are commercially available underthe designations VISTAMAXX™ (e.g., 2330, 6202, and 6102), apropylene-ethylene copolymer-based plastomer from ExxonMobil ChemicalCo. of Houston, Texas; FINA™ (e.g., 8573) from Atofina Chemicals ofFeluy, Belgium; TAFMER™ available from Mitsui Petrochemical Industries;and VERSIFY™ available from Dow Chemical Co. of Midland, Michigan. Otherexamples of suitable propylene polymers are described in U.S. Pat. No.6,500,563 to Datta, et al.; U.S. Pat. No. 5,539,056 to Yang, et al.; andU.S. Pat. No. 5,596,052 to Resconi, et al., which are incorporatedherein in their entirety by reference thereto for all purposes.

Any of a variety of known techniques may generally be employed to formthe semi-crystalline polyolefins. For instance, olefin polymers may beformed using a free radical or a coordination catalyst (e.g.,Ziegler-Natta). Preferably, the olefin polymer is formed from asingle-site coordination catalyst, such as a metallocene catalyst. Sucha catalyst system produces ethylene copolymers in which the comonomer israndomly distributed within a molecular chain and uniformly distributedacross the different molecular weight fractions. Metallocene-catalyzedpolyolefins are described, for instance, in U.S. Pat. No. 5,571,619 toMcAlpin et al.; U.S. Pat. No. 5,322,728 to Davis et al.; U.S. Pat. No.5,472,775 to Obiieski et al.; U.S. Pat. No. 5,272,236 to Lai et al.; andU.S. Pat. No. 6,090,325 to Wheat, et al., which are incorporated hereinin their entirety by reference thereto for all purposes. Examples ofmetallocene catalysts include bis(n-butylcyclopentadienyl)titaniumdichloride, bis(n-butylcyclopentadienyl)zirconium dichloride,bis(cyclopentadienyl)scandium chloride, bis(indenyl)zirconiumdichloride, bis(methylcyclopentadienyl)titanium dichloride,bis(methylcyclopentadienyl)zirconium dichloride, cobaltocene,cyclopentadienyltitanium trichloride, ferrocene, hafnocene dichloride,isopropyl(cyclopentadienyl,-1-flourenyl)zirconium dichloride,molybdocene dichloride, nickelocene, niobocene dichloride, ruthenocene,titanocene dichloride, zirconocene chloride hydride, zirconocenedichloride, and so forth. Polymers made using metallocene catalyststypically have a narrow molecular weight range. For instance,metallocene-catalyzed polymers may have polydispersity numbers(M_(w)/M_(n)) of below 4, controlled short chain branching distribution,and controlled isotacticity.

The melt flow index (MI) of the semi-crystalline polyolefins maygenerally vary, but is typically in the range of about 0.1 grams per 10minutes to about 100 grams per 10 minutes, in some embodiments fromabout 0.5 grams per 10 minutes to about 30 grams per 10 minutes, and insome embodiments, about 1 to about 10 grams per 10 minutes, determinedat 190° C. The melt flow index is the weight of the polymer (in grams)that may be forced through an extrusion rheometer orifice (0.0825-inchdiameter) when subjected to a force of 5000 grams in 10 minutes at 190°C., and may be determined in accordance with ASTM Test Method D1238-E.

Of course, other thermoplastic polymers may also be used to formnonwoven web material. For instance, a substantially amorphous blockcopolymer may be employed that has at least two blocks of a monoalkenylarene polymer separated by at least one block of a saturated conjugateddiene polymer. The monoalkenyl arene blocks may include styrene and itsanalogues and homologues, such as o-methyl styrene; p-methyl styrene;p-tert-butyl styrene; 1,3 dimethyl styrene p-methyl styrene; etc., aswell as other monoalkenyl polycyclic aromatic compounds, such as vinylnaphthalene; vinyl anthrycene; and so forth. Preferred monoalkenylarenes are styrene and p-methyl styrene. The conjugated diene blocks mayinclude homopolymers of conjugated diene monomers, copolymers of two ormore conjugated dienes, and copolymers of one or more of the dienes withanother monomer in which the blocks are predominantly conjugated dieneunits. Preferably, the conjugated dienes contain from 4 to 8 carbonatoms, such as 1,3 butadiene (butadiene); 2-methyl-1,3 butadiene;isoprene; 2,3 dimethyl-1,3 butadiene; 1,3 pentadiene (piperylene); 1,3hexadiene; and so forth.

The amount of monoalkenyl arene (e.g., polystyrene) blocks may vary, buttypically constitute from about 8 wt. % to about 55 wt. %, in someembodiments from about 10 wt. % to about 35 wt. %, and in someembodiments, from about 25 wt. % to about 35 wt. % of the copolymer.Suitable block copolymers may contain monoalkenyl arene endblocks havinga number average molecular weight from about 5,000 to about 35,000 andsaturated conjugated diene midblocks having a number average molecularweight from about 20,000 to about 170,000. The total number averagemolecular weight of the block polymer may be from about 30,000 to about250,000.

Particularly suitable thermoplastic elastomeric block copolymers areavailable from Kraton Polymers LLC of Houston, Texas under the tradename KRATON™. KRATON™ polymers include styrene-diene block copolymers,such as styrene-butadiene, styrene-isoprene, styrene-butadiene-styrene,and styrene-isoprene-styrene. KRATON™ polymers also includestyrene-olefin block copolymers formed by selective hydrogenation ofstyrene-diene block copolymers. Examples of such styrene-olefin blockcopolymers include styrene-(ethylene-butylene),styrene-(ethylene-propylene), styrene-(ethylene-butylene)-styrene,styrene-(ethylene-propylene)-styrene,styrene-(ethylene-butylene)-styrene-(ethylene-butylene),styrene-(ethylene-propylene)-styrene-(ethylene-propylene), andstyrene-ethylene-(ethylene-propylene)-styrene. These block copolymersmay have a linear, radial or star-shaped molecular configuration.Specific KRATON™ block copolymers include those sold under the brandnames G 1652, G 1657, G 1730, MD6673, MD6703, MD6716, and MD6973.Various suitable styrenic block copolymers are described in U.S. Pat.Nos. 4,663,220, 4,323,534, 4,834,738, 5,093,422 and 5,304,599, which arehereby incorporated in their entirety by reference thereto for allpurposes. Other commercially available block copolymers include theS-EP-S and S-E-E-P-S elastomeric copolymers available from KurarayCompany, Ltd. of Okayama, Japan, under the trade designation SEFTON™.Still other suitable copolymers include the S-I-S and S-B-S elastomericcopolymers available from Dexco Polymers of Houston, Texas under thetrade designation VECTOR™. Also suitable are polymers composed of anA-B-A-B tetrablock copolymer, such as discussed in U.S. Pat. No.5,332,613 to Taylor, et al., which is incorporated herein in itsentirety by reference thereto for all purposes. An example of such atetrablock copolymer is astyrene-poly(ethylene-propylene)-styrene-poly(ethylene-propylene)(“S-EP-S-EP”) block copolymer.

A single polymer as discussed above can be used to form the fibers fromwhich the nonwoven web material is comprised, and when utilized, can beutilized in amount up to 100 wt. % based on the total weight of thenonwoven web material, such as from about 75 wt. % to about 99 wt. %,such as from about 80 wt. % to about 98 wt. %, such as from about 85 wt.% to about 95 wt. %. However, in other embodiments, the nonwoven webmaterial can include two or more polymers from the polymers discussedabove. For instance, monocomponent fibers from which the nonwoven webmaterial can include fibers formed from an olefin homopolymer in anamount ranging from about 5 wt. % to about 80 wt. %, such as from about10 wt. % to about 75 wt. %, such as from about 15 wt. % to about 70 wt.%, based on the total weight of the nonwoven web material. Meanwhile,the fibers can also include a derivative of an olefin polymer. Forinstance, the nonwoven web material can include an elastomericsemi-crystalline polyolefin or “plastomer” (e.g., an ethylene/α-olefincopolymer, a propylene/α-olefin copolymer, or a combination thereof); athermoplastic elastomeric block copolymer; or a combination thereof inan amount ranging from about 20 wt. % to about 95 wt. %, such as fromabout 25 wt. % to about 90 wt. %, such as from about 30 wt. % to about85 wt. % based on the total weight of the nonwoven web material.

In additional embodiments, the fibers from which the nonwoven webmaterial is formed can be multicomponent and can have a sheath-corearrangement or side-by-side arrangement. For instance, in a sheath-coremulticomponent fiber arrangement, the sheath can include a blend of apolypropylene and a polypropylene-based plastomer, (e.g., VISTAMAXX™),while the core can include a blend of a polyethylene and apolyethylene-based plastomer (e.g., INFUSE™). On the other hand, thesheath can include a blend of a polyethylene and a polyethylene-basedplastomer (e.g., INFUSE™), while the core can include a blend of apolypropylene and a polypropylene-based plastomer, (e.g., VISTAMAXX™).Further, in still other embodiments, the core can include 100% of apolyethylene or a polypropylene homopolymer.

For instance, in some embodiments, the fibers from which the nonwovenweb material is formed can have a sheath-core arrangement where thesheath can include from about 20 wt. % to about 90 wt. %, such as fromabout 25 wt. % to about 80 wt. %, such as from about 30 wt. % to about70 wt. % of an olefin homopolymer (e.g., polypropylene or polyethylene)based on the total weight of the sheath component of the multicomponentfiber. Meanwhile, the sheath can also include from about 10 wt. % toabout 80 wt. %, such as from about 20 wt. % to about 75 wt. %, such asfrom about 30 wt. % to about 70 wt. % of an olefin-based plastomer(e.g., a polypropylene-based plastomer or an ethylene-based plastomer)based on the total weight of the sheath component of the multicomponentfiber.

In addition, the core can include from about 30 wt. % to about 100 wt.%, such as from about 40 wt. % to about 95 wt. %, such as from about 50wt. % to about 90 wt. % of an olefin homopolymer (e.g., polypropylene orpolyethylene) based on the total weight of the core component of themulticomponent fiber. Further, the core can include from about 0 wt. %to about 70 wt. %, such as from about 5 wt. % to about 60 wt. %, such asfrom about 10 wt. % to about 50 wt. % of an olefin-based plastomer(e.g., a polypropylene-based plastomer or an ethylene-based plastomer)based on the total weight of the core component of the fiber.

Further, the weight percentage of the sheath can range from about 10 wt.% to about 70 wt. %, such as from about 15 wt. % to about 65 wt. %, suchas from about 20 wt. % to about 60 wt. %, based on the total weight ofthe fiber. Meanwhile, the weight percentage of the core can range fromabout 30 wt. % to about 90 wt. %, such as from about 35 wt. % to about85 wt. %, such as from about 40 wt. % to about 80 wt. % based on thetotal weight of the fiber.

In addition, the fibers from which the nonwoven web material is formedcan have a side-by-side arrangement where two fibers are coextrudedadjacent each other. In such an embodiment, the first side can include apolyethylene and a polyethylene-based plastomer, while the second sidecan include a polypropylene and a polypropylene-based plastomer. Thepolyethylene can be present in the first side in an amount ranging fromabout 30 wt. % to about 90 wt. %, such as from about 35 wt. % to about80 wt. %, such as from about 40 wt. % to about 70 wt. % based on thetotal weight of the first side. Meanwhile, the polyethylene-basedplastomer can be present in the first side in an amount ranging fromabout 20 wt. % to about 80 wt. %, such as from about 25 wt. % to about70 wt. %, such as from about 30 wt. % to about 60 wt. % based on thetotal weight of the first side. In addition, the polypropylene can bepresent in the second side in an amount ranging from about 30 wt. % toabout 90 wt. %, such as from about 35 wt. % to about 80 wt. %, such asfrom about 40 wt. % to about 70 wt. % based on the total weight of thesecond side. Meanwhile, the polypropylene-based plastomer can be presentin the second side in an amount ranging from about 20 wt. % to about 80wt. %, such as from about 25 wt. % to about 70 wt. %, such as from about30 wt. % to about 60 wt. % based on the total weight of the second side.

With such fiber configurations as those discussed above, in someembodiments, a propylene-ethylene copolymer can be utilized in eitherthe sheath and/or the core or the first side and/or the second side toact as a compatibilizer and enhance bonding between the sheath and core.For instance, the propylene-ethylene copolymer can be present in thesheath in an amount ranging from about 0.5 wt. % to about 20 wt. %, suchas from about 1 wt. % to about 15 wt. %, such as from about 2 wt. % toabout 10 wt. % based on the total weight of the sheath. Alternatively,the propylene-ethylene copolymer can be present in the core in an amountranging from about 0.5 wt. % to about 20 wt. %, such as from about 1 wt.% to about 15 wt. %, such as from about 2 wt. % to about 10 wt. % basedon the total weight of the core.

Other additives may also be incorporated into the nonwoven web material,such as melt stabilizers, processing stabilizers, heat stabilizers,light stabilizers, antioxidants, heat aging stabilizers, whiteningagents, antiblocking agents, viscosity modifiers, etc. Viscositymodifiers may also be employed, such as polyethylene wax (e.g., EPOLENE™C-10 from Eastman Chemical). Phosphite stabilizers (e.g., IRGAFOSavailable from Ciba Specialty Chemicals of Tarrytown, N.Y. and DOVERPHOSavailable from Dover Chemical Corp. of Dover, Ohio) are exemplary meltstabilizers. In addition, hindered amine stabilizers (e.g., CHIMASSORBavailable from Ciba Specialty Chemicals) are exemplary heat and lightstabilizers. Further, hindered phenols are commonly used as anantioxidant in the production of films. Some suitable hindered phenolsinclude those available from Ciba Specialty Chemicals of under the tradename IRAGANOX™, such as IRGANOX™ 1076, 1010, or E 201. When employed,such additives (e.g., antioxidant, stabilizer, etc.) may each be presentin an amount from about 0.001 wt. % to about 25 wt. %, in someembodiments, from about 0.005 wt. % to about 20 wt. %, and in someembodiments, from 0.01 wt. % to about 15 wt. % of the nonwoven webmaterial.

The polymer(s) discussed above, as well as the other optional additivecomponents discussed above, can be formed into monocomponent ormulticomponent fibers and extruded or spun to form the nonwoven webmaterial of the present invention, which can then be used in variousproducts such a wipe, an absorbent article, a wearable article, or thelike, and discussed in more detail below. Monocomponent fibers can beformed from a polymer or a blend of polymers as well as an optionaltackifier, which are compounded and then extruded from a singleextruder. Meanwhile, multicomponent fibers can be formed from two ormore polymers (e.g., bicomponent fibers) extruded from separateextruders, where one or more of the polymers can be compounded with atackifier, although this is not required when one of the polymersexhibits inherent tackiness, such as VISTAMAXX™ polymers and INFUSE™polymers. The polymers may be arranged in substantially constantlypositioned distinct zones across the cross-section of the fibers. Thecomponents may be arranged in any desired configuration, such assheath-core, side-by-side, pie, island-in-the-sea, three island, bull'seye, or various other arrangements known in the art, and so forth.Various methods for forming multicomponent fibers are described in U.S.Pat. No. 4,789,592 to Taniguchi et al. to Strack et al., U.S. Pat. No.5,108,820 to Kaneko, et al., U.S. Pat. No. 4,795,668 to Krueqe, et al.,U.S. Pat. No. 5,382,400 to Pike, et al., U.S. Pat. No. 5,336,552 toStrack, et al., and U.S. Pat. No. 6,200,669 to Marmon, et al., which areincorporated herein in their entirety by reference thereto for allpurposes. Multicomponent fibers having various irregular shapes may alsobe formed, such as described in U.S. Pat. No. 5,277,976 to Haile, etal., to Hills, U.S. Pat. No. 5,466,410 to Hills, U.S. Pat. No. 5,069,970to Largman, et al., and U.S. Pat. No. 5,057,368 to Largman, et al.,which are incorporated herein in their entirety by reference thereto forall purposes. In addition, hollow fibers are also contemplated by thepresent invention, and such fibers can reduce the amount of polymerrequired, as well as the basis weight of the resulting nonwoven webmaterial.

In any event, whether the nonwoven web material is formed bymeltblowing, spunbonding, or any other nonwoven web material technique,when a tackifier and/or any optional additives are compounded with oneor more polymers However, it is also to be understood that, in someembodiments, the core can be a blend of two or more polymers such aspolypropylene and a VISTAMAXX™ plastomer, while the sheath can also be ablend of two or polymers such as polyethylene and an INFUSE™ plastomer.Generally, the composition of the core can be chosen such that theresulting overall material is cloth-like, drapable, and soft, while thecomposition of the sheath can be chosen such that the sheath providesthe level of tackiness needed for efficient dirt removal without theuser experiencing stick and slip motion, while at the same time leavingno residue.

Various embodiments of forming the fibers and nonwoven web material ofthe present invention will now be described in greater detail. Ofcourse, it should be understood that the description provided below ismerely exemplary, and that other methods of forming nonwoven webmaterials are contemplated by the present Disclosure. Particularly, thenonwoven web material can be formed from meltblown fibers or by othermethods than meltblowing, such as spunbonding. One advantage of formingthe nonwoven web material by spunbonding is that higher molecular weightpolymers can be utilized as compared to the polymers used to form ameltblown nonwoven web material because the size of the capillary diesused in spunbonding equipment is larger than in meltblowing equipment.However, it is also to be understood that in the case of forming ameltblown nonwoven web material, the size of the capillary of the meltblown die can be increased to accommodate high viscosity (e.g., highmolecular weight. Generally, however, the melt flow rate of the polymersof the present invention can range from about 3 grams per 10 minutes toabout 50 grams per 10 minutes when subjected to a load of 2160 grams ata temperature of 190° C. according to ASTM Test Method D1238-E. As such,in forming spunbond nonwoven web materials, polymers having higherviscosity and crystallinity can be used. For instance, polypropylenehaving a melt flow rate of from about 15 grams per 10 minutes to about50 grams per 10 minutes, such as from about 20 grams per 10 minutes toabout 35 grams per 10 minutes; olefinic block copolymer plastomershaving a melt flow rate of from about 3 grams per 10 minutes to about 20grams per 10 minutes, such as from about grams per 10 minutes to about15 grams per 10 minutes; and polyethylenes having a melt flow rate offrom about 5 grams per 10 minutes to about 30 grams per 10 minutes, suchas from about 10 grams per 10 minutes to about 25 grams per 10 minutescan be utilized.

If desired, the nonwoven web material may have a multi-layer structure.Suitable multi-layered materials may include, for instance,spunbond/meltblown/spunbond (SMS) laminates and spunbond/meltblown (SM)laminates, where the spunbond and meltblown layers are formed generallyas discussed above. However, in one aspect, the present disclosureincludes nonwoven webs and/or base sheets that are free of SMSlaminates. Particularly, as discussed above, nonwoven webs according tothe present disclosure may instead have properties introduced to thenonwoven web via the adhered staple fibers, and may therefore notrequire any of the traditional benefits associated with SMS laminates.

Another example of a nonwoven web material that is contemplated by thepresent invention is a spunbond web produced on a multiple spin bankmachine in which a spin bank deposits fibers over a layer of fibersdeposited from a previous spin bank. Such an individual spunbondnonwoven web may also be thought of as a multi-layered structure. Inthis situation, the various layers of deposited fibers in the nonwovenweb may be the same, or they may be different in basis weight and/or interms of the composition, type, size, level of crimp, and/or shape ofthe fibers produced. As another example, a single nonwoven web may beprovided as two or more individually produced layers of a spunbond web,a carded web, etc., which have been bonded together to form the nonwovenweb. These individually produced layers may differ in terms ofproduction method, basis weight, composition, and fibers.

A nonwoven web material as contemplated by the present invention mayalso contain an additional fibrous component such that it is considereda composite. For example, a nonwoven web may be entangled with anotherfibrous component using any of a variety of entanglement techniquesknown in the art (e.g., hydraulic, air, mechanical, etc.). In oneembodiment, a nonwoven web formed from one polymer can be integrallyentangled with fibers containing another polymer using hydraulicentanglement. A typical hydraulic entangling process utilizes highpressure jet streams of water to entangle fibers to form a highlyentangled consolidated fibrous structure, e.g., a nonwoven web.Hydraulically entangled nonwoven webs are disclosed, for example, inU.S. Pat. No. 3,494,821 to Evans and U.S. Pat. No. 4,144,370 to Boulton,which are incorporated herein in their entirety by reference thereto forall purposes. The fibrous component of the composite may contain anydesired amount of the resulting composite. For instance, the fibrouscomponent may contain greater than about 50% by weight of the composite,and in some embodiments, from about 60% to about 90% by weight of thecomposite. Likewise, the nonwoven web may contain less than about 50% byweight of the composite, and in some embodiments, from about 10% toabout 40% by weight of the composite. In some embodiments, the nonwovenweb can include a spunbond polyolefin-based web (e.g., polypropylene orpolyethylene), while the fibrous component can include fibers containinga blend of polypropylene and VISTAMAXX™ or any other propylene-basedplastomer, or a blend of polyethylene and INFUSE™ or any other suitableethylene-based plastomer.

The nonwoven web material can also be hydroentangled. Hydroentanglednonwoven webs are disclosed, for example, in U.S. Pat. No. 7,779,521 toTopolkaraev, et al. With hydroentangling, layer of fibers is depositedon a foraminous support. The foraminous support is commonly a continuouswire screen, sometimes called a forming fabric. Forming fabrics arecommonly used in the nonwovens industry and particular types arerecognized by those skilled in the art as being advantageous forhydroentangling purposes. Alternatively, the foraminous support may bethe surface of a cylinder, and generally may be any surface thatsupports the fibers and transports them under the water jets or watercurtain that impart the energy to entangle the fibers. Innovent Inc. ofPeabody, Mass., USA, the aforementioned Rieter Perfojetand, andFleissner sell screens and cylinders suitable for this purpose.

Typically the foraminous support has holes to allow water drainage, butalternatively or additionally the foraminous support may have elevationsor grooves, to allow drainage and impart topographic features on thefinished fabric. In this context “water” indicates a fluid that ispredominantly water, but may contain intentional or unintentionaladditives, including minerals, surfactants, defoamers, and variousprocessing aides.

When the fibers are deposited on the support they may be completelyunbonded, alternatively the fibers may be lightly bonded in the form ofa nonwoven when they are deposited on the foraminous support. In otheraspects of this invention, unbonded fibers may be deposited on thesupport and prior to hydroentangling the fibers may be lightly bondedusing heat or other means. It is generally desirable that the fiberspassing under the water jets have sufficient motility to efficientlyhydroentangle.

The general conditions of hydroentangling, i.e., water pressure,nozzle-type, design of the foraminous support, are well known to thoseskilled in the art. “Hydroentangle” and its derivatives refer to aprocess for forming a fabric by mechanically wrapping and knottingfibers into a web through the use of a high-velocity jets or curtains ofwater. The resulting hydroentangled fabric is sometimes called“spunlaced” or “hydroknit” in the literature.

Generally, a high pressure water system delivers water to nozzles ororifices from which high velocity water is expelled. The layer of fibersis transported on the foraminous support member through at least onehigh velocity water jet or curtain. Alternatively, more than one waterjet or curtain may be used. The direct impact of the water on the fiberscauses the fibers to wind and twist and entangle around nearby fibers.Additionally, some of the water may rebound off the foraminous supportmember, this rebounding water also contributes to entanglement. Thewater used for hydroentangling is then drained into a manifold,typically from beneath the support member, and generally recirculated.As a result of the hydroentangling process, the fibers are convertedinto a coherent fabric.

Regardless of the type of nonwoven web material formed, the basis weightof the nonwoven web material may generally vary, such as from about 10grams per square meter (“gsm”) to about 150 gsm, in some embodimentsfrom about 20 gsm to about 125 gsm, and in some embodiments, from about25 gsm to about 100 gsm. When multiple nonwoven web materials are used,such materials may have the same or different basis weights.

Furthermore, the present disclosure also generally includes a method offorming a base sheet according to the present disclosure. For instance,referring to FIG. 3 , a nonwoven web 202, formed according to any methodknown in the art using the above discussed materials or the like may beunwound from a first roll 204. The nonwoven web 202 can undergo variousprocesses as known in the art, including embossing (not shown) and hasan adhesive 206 applied thereto. As shown in FIG. 3 , the presentdisclosure has found that the adhesive may be applied in-line using aflexographic printer 208. However, it should be understood that, in someaspects, other application methods may be used. Nonetheless, thenonwoven web 202 having the adhesive 206 applied thereto, enters anelectroplating apparatus 210 containing staple fibers treated with acation. As known in the art, the electroplating module 210 contains anelectrode, and an electrolyte, causing the plurality of staple fibers tobe plated or deposited onto the anion containing adhesive 206. Finally,in one aspect, the nonwoven web 202 containing the electroplated fibers210 may be calandered 212 to further improve fiber adhesion before beingwound on roll 214 as a base sheet according to the present disclosure.

Once the meltblown nonwoven web material, the spunbond nonwoven webmaterial, or any other nonwoven web material is formed, and either priorto or after undergoing electroplating and/or calandering, the nonwovenweb material can be further processed to reduce lint left behind whenthe nonwoven web material is used, to minimize the amount of residue orstreaks present on a surface after the surface is contacted with thenonwoven web material, and to enhance the dust holding capacity of thenonwoven web material.

For instance, as discussed above, the nonwoven web material can beapertured, post-bonded, or both. Aperturing can enhance the dust holdingcapacity of the nonwoven web material by creating pockets in thenonwoven web material in which particulates, dust, pathogens, etc. canbe trapped. Aperturing can occur by any suitable method known to onehaving ordinary skill in the art, such as laser aperturing, slitaperturing, pin aperturing, or thermal aperturing using a patternedroll. Meanwhile post-bonding can reduce the amount of lint produced bythe nonwoven web material and can also enhance the dust holding capacityof the nonwoven web material by creating indentations in the nonwovenweb material in which particulates, dust, pathogens, etc. can betrapped. Although not required, the processes to form apertures andbonds in the nonwoven web material can occur concurrently. However, itshould be understood that other methods of forming the apertures andbonds that are not concurrent can also be utilized, as is known to thosehaving ordinary skill in the art. To concurrently form apertures andtextured elements on the nonwoven web material, a patterned bondingtechnique (e.g., thermal point bonding, ultrasonic bonding, etc.) isgenerally used in which the nonwoven web material is supplied to a nipdefined by at least one patterned roll. Thermal point bonding, forinstance, typically employs a nip formed between two rolls, at least oneof which is patterned. Ultrasonic bonding, on the other hand, typicallyemploys a nip formed between a sonic horn and a patterned roll.Regardless of the technique chosen, the patterned roll contains aplurality of raised bonding elements to concurrently bond the nonwovenweb material and form apertures in the nonwoven web material.

The size of the bonding elements may be specifically tailored tofacilitate the formation of apertures in the nonwoven web material andenhance bonding between the fibers contained in the nonwoven webmaterial. For example, the length dimension of the bonding elements maybe from about 300 to about 5000 micrometers, in some embodiments fromabout 500 to about 4000 micrometers, and in some embodiments, from about1000 to about 2000 micrometers. The width dimension of the bondingelements may likewise range from about 20 to about 500 micrometers, insome embodiments from about 40 to about 200 micrometers, and in someembodiments, from about to about 150 micrometers. In addition, the“element aspect ratio” (the ratio of the length of an element to itswidth) may range from about 2 to about 100, in some embodiments fromabout 4 to about 50, and in some embodiments, from about 5 to about 20.

Besides the size of the bonding elements, the overall bonding patternmay also be selectively controlled to achieve the desired apertureformation. In one embodiment, for example, a bonding pattern is selectedin which the longitudinal axis (longest dimension along a center line ofthe element) of one or more of the bonding elements is skewed relativeto the machine direction (“MD”) of the nonwoven web material. Forexample, one or more of the bonding elements may be oriented from about30° to about 150°, in some embodiments from about 45° to about 135°, andin some embodiments, from about 60° to about 120° relative to themachine direction of the nonwoven web material. In this manner, thebonding elements will present a relatively large surface to the nonwovenweb material in a direction substantially perpendicular to that whichthe nonwoven web material moves. This increases the area over whichshear stress is imparted to the nonwoven web material and, in turn,facilitates aperture formation.

The pattern of the bonding elements is generally selected so that thenonwoven web material has a total bond area of less than about 50% (asdetermined by conventional optical microscopic methods), in someembodiments, less than about 40%, and in some embodiments, less thanabout 25%. The bond density is also typically greater than about 50bonds per square inch, and in some embodiments, from about 75 to about500 pin bonds per square inch. One suitable bonding pattern for use inthe present invention is known as an “S-weave” pattern and is describedin U.S. Pat. No. 5,964,742 to McCormack, et al., which is incorporatedherein in its entirety by reference thereto for all purposes. S-weavepatterns typically have a bonding element density of from about 50 toabout 500 bonding elements per square inch, and in some embodiments,from about 75 to about 150 bonding elements per square inch. An exampleof a suitable “S-weave” pattern in shown in FIG. 9 , which illustratesS-shaped bonding elements 88 having a length dimension “L” and a widthdimension “W.” Another suitable bonding pattern is known as the“rib-knit” pattern and is described in U.S. Pat. No. 5,620,779 to Levy,et al., which is incorporated herein in its entirety by referencethereto for all purposes. Rib-knit patterns typically have a bondingelement density of from about 150 to about 400 bonding elements persquare inch, and in some embodiments, from about 200 to about 300bonding elements per square inch. An example of a suitable “rib-knit”pattern in shown in FIG. 10 , which illustrates bonding elements 89 andbonding elements 91, which are oriented in a different direction. Yetanother suitable pattern is the “wire weave” pattern, which has abonding element density of from about 200 to about 500 bonding elementsper square inch, and in some embodiments, from about 250 to about 350bonding elements per square inch. An example of a suitable “wire-weave”pattern in shown in FIG. 11 , which illustrates bonding elements 93 andbonding elements 95, which are oriented in a different direction. Otherbond patterns that may be used in the present invention are described inU.S. Pat. No. 3,855,046 to Hansen et al.; U.S. Pat. No. 5,962,112 toHaynes et al.; U.S. Pat. No. 6,093,665 to Sayovitz et al.; D375,844 toEdwards, et al.; D428,267 to Romano et al.; and D390,708 to Brown, whichare incorporated herein in their entirety by reference thereto for allpurposes.

The selection of an appropriate bonding temperature (e.g., thetemperature of a heated roll) will help melt and/soften nonwoven webmaterial at regions adjacent to the bonding elements. The softenednonwoven web material may then flow and become displaced during bonding,such as by pressure exerted by the bonding elements.

To achieve such concurrent aperture and bond formation withoutsubstantially softening the polymer(s) of the nonwoven web material, thebonding temperature and pressure may be selectively controlled. Forexample, one or more rolls may be heated to a surface temperature offrom about 50° C. to about 160° C., in some embodiments from about 60°C. to about 140° C., and in some embodiments, from about 70° C. to about120° C. Likewise, the pressure exerted by rolls (“nip pressure”) duringthermal bonding may range from about 75 to about 600 pounds per linearinch (about 1339 to about 10,715 kilograms per meter), in someembodiments from about 100 to about 400 pounds per linear inch (about1786 to about 7143 kilograms per meter), and in some embodiments, fromabout 120 to about 200 pounds per linear inch (about 2143 to about 3572kilograms per meter). Of course, the residence time of the materials mayinfluence the particular bonding parameters employed.

Another factor that influences concurrent aperture and bond formation isthe degree of tension in the nonwoven web material. An increase innonwoven web material tension when it is passed over the bondingelements, for example, typically correlates to an increase in aperturesize. Of course, a tension that is too high may adversely affect theintegrity of the nonwoven web material, which could negatively impactthe ability to form a cloth with sufficient tackiness and minimal lintproduction. Thus, in most embodiments of the present invention, astretch ratio of about 1.5 or more, in some embodiments from about 2.5to about 7.0, and in some embodiments, from about 3.0 to about 5.5, isemployed to achieve the desired degree of tension in the film duringlamination. The stretch ratio may be determined by dividing the finallength of the film by its original length.

Generally, the size and/or pattern of the resulting apertures in thenonwoven web material correspond to the size and/or pattern of thebonding elements discussed above. That is, the apertures may have alength, width, aspect ratio, and orientation as described above. Forexample, the length dimension of the apertures may be from about 200 toabout 5000 micrometers, in some embodiments from about 350 to about 4000micrometers, and in some embodiments, from about 500 to about 2500micrometers. The width dimension of the apertures may likewise rangefrom about 20 to about 500 micrometers, in some embodiments from about40 to about 200 micrometers, and in some embodiments, from about 50 toabout 150 micrometers. In addition, the “aspect ratio” (the ratio of thelength of an aperture to its width) may range from about 2 to about 100,in some embodiments from about 4 to about 50, and in some embodiments,from about 5 to about 20. Similarly, the longitudinal axis of one ormore of the apertures (longest dimension along a center line of theaperture) may be skewed relative to the machine direction of thenonwoven web material, such as from about 30° to about 150°, in someembodiments from about 45° to about 135°, and in some embodiments, fromabout 60° to about 120° relative to the machine direction of thenonwoven web material.

Furthermore, certain aspects of the present disclosure may be betterunderstood according to the following examples, which are intended to benon-limiting and exemplary in nature.

EXAMPLES

Cup Crush: The softness of a nonwoven fabric may be measured accordingto the “cup crush” test. The cup crush test evaluates fabric stiffnessby measuring the peak load (also called the “cup crush load” or just“cup crush”) required for a 4.5 cm diameter hemispherically shaped footto crush a 23 cm by 23 cm piece of fabric shaped into an approximately6.5 cm diameter by 6.5 cm tall inverted cup while the cup shaped fabricis surrounded by an approximately 6.5 cm diameter cylinder to maintain auniform deformation of the cup shaped fabric. An average of 10 readingsis used. The foot and the cup are aligned to avoid contact between thecup walls and the foot which could affect the readings. The peak load ismeasured while the foot is descending at a rate of about 0.25 inches persecond (380 mm per minute) and is measured in grams. The cup crush testalso yields a value for the total energy required to crush a sample (the“cup crush energy”) which is the energy from the start of the test tothe peak load point, i.e. the area under the curve formed by the load ingrams on one axis and the distance the foot travels in millimeters onthe other. Cup crush energy is therefore reported in gm-mm. Lower cupcrush values indicate a softer laminate. A suitable device for measuringcup crush is a model FTD-G-500 load cell (500 gram range) available fromthe Schaevitz Company, Pennsauken, N.J.

Example 1

A spunbond/spunbond nonwoven web having a basis weight of about 23 gsmand barrier properties was formed. A water-based adhesive treated withan anionic agent supplied by Agatex was applied by flexographic printingto the nonwoven web at a thickness of 100 micrometers. Polyethylenestaple fibers having a denier of about 1.5 and having a length of 500micrometers treated with a cation supplied by Agatex were adhered to thenonwoven web using an electroplating apparatus described above, forminga base sheet. The base sheet exhibited improved softness whilemaintaining good barrier properties. For instance, after attachment ofthe staple fibers, the base sheet exhibited a bacterial filtrationefficiency of 98.2% as measured according to UNE-EN 14683:2019 annex B,a breathability of 14.1 Pa/cm² as measured according to UNE-EN14683:2019 annex C, and a splash resistance of less than 10.6 kPa asmeasured according to ISO 22609:2004 ASTM F1862.

Example 2

A polypropylene nonwoven web coformed with pulp fibers was preparedhaving a basis weight of about 82 gsm. A water-based adhesive treatedwith an anionic agent supplied by Agatex was applied to the nonwoven webvia flexographic printing at a thickness of 100 micrometers.Polyethylene staple fibers having a denier of about 1.5 and having alength of 500 micrometers were treated with a cation supplied by Agatex,and adhered to the nonwoven web using an electroplating apparatusdescribed above, forming a 150 gsm base sheet with 15% improvement inabrasion as compared to the same nonwoven web without the plurality ofstaple fibers.

These and other modifications and variations to the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention, which ismore particularly set forth in the appended claims. In addition, itshould be understood that aspects of the various aspects may beinterchanged both in whole or in part. Furthermore, those of ordinaryskill in the art will appreciate that the foregoing description is byway of example only, and is not intended to limit the invention sofurther described in such appended claims.

1. A base sheet having a microstructured topography comprising: anonwoven web comprising a first surface, and an opposed second surface,wherein the nonwoven web extends in a first plane; an adhesive; and aplurality of staple fibers affixed to the first surface of the nonwovenweb by the adhesive, wherein at least a portion of the plurality ofstaple fibers extend in one or more second planes, wherein the one ormore second planes are not parallel to the first plane, and wherein atleast a portion of the staple fibers have a length of about 5000micrometers or less, a denier of about 5 or less, or a combinationthereof; and wherein the nonwoven web exhibits: a liquid capacity ofabout 200% to about 800%, measured as an increase in a weight of thenonwoven web from absorption of a liquid, a cup crush load of less thanabout 100 grams, when measured using a 34 gsm nonwoven web, a bacterialfiltration efficiency of about 80% or greater, or a combination thereof.2. The base sheet as defined in claim 1, wherein the base sheet is awiping product or an absorbent article.
 3. The base sheet as defined inclaim 1, wherein the at least a portion of staple fibers have a lengthof about 1500 micrometers or less and a denier of about 3 or less, or alength of about 1500 micrometers to about 5000 micrometers, and a denierof about 3 to about
 5. 4. The base sheet as defined in claim 1, whereinthe nonwoven web comprises elastomeric fibers, three-dimensional fibers,debonded cellulosic fibers, pulp fibers, or mixtures thereof.
 5. Thebase sheet as defined claim 1, wherein the nonwoven web comprisespolyethylene fibers, polyethylene fibers, pulp fibers, or a combinationthereof.
 6. The base sheet as defined in claim 1, wherein the nonwovenweb is a spunbond nonwoven web.
 7. The base sheet as defined in claim 1,wherein the plurality of staple fibers comprise polyethylene fibers,polypropylene fibers, rayon fibers, nylon fibers, or a combinationthereof.
 8. The base sheet as defined claim 1, wherein the adhesivecomprises an anionic component, the plurality of staple fibers contain acation, or a combination thereof.
 9. The base sheet as defined in claim1, wherein the anionic component and adhesive are coated on at least aportion of the nonwoven web.
 10. The base sheet as defined in claim 1,wherein 50% or more of the nonwoven web is coated with the anioniccomponent and an adhesive.
 11. The base sheet as defined in claim 1,wherein the anionic component and adhesive are applied on the nonwovenweb in a pattern that includes circles, squares, lines, or a combinationthereof.
 12. The base sheet as defined in claim 1, wherein nonwoven webis embossed.
 13. The base sheet as defined in claim 1, furthercomprising a second plurality of staple fibers adhered to the secondsurface of the nonwoven web by an adhesive.
 14. The base sheet asdefined in claim 13, wherein the second plurality of staple fibers havea different length, denier, or fiber composition than the firstplurality of staple fibers, or a combination thereof.
 15. (canceled) 16.The base sheet as defined in claim 1, wherein the base sheet exhibits a10% or greater improvement in one or more of water capacity, cup crushload, or bacterial filtration, as compared to the same nonwoven web thatdoes not include the plurality of staple fibers.
 17. A method of forminga base sheet, comprising; forming a nonwoven web that extends in a firstplane; applying an adhesive to a first surface of the nonwoven web; andadhering a plurality of staple fibers to the nonwoven web, wherein atleast a portion of the plurality of staple fibers extend in one or moresecond planes, wherein the one or more second planes are not parallel tothe first plane, and wherein at least a portion of the staple fibershave a length of about 5000 micrometers or less, a denier of 5 or less,or a combination thereof; and wherein the nonwoven web exhibits: aliquid capacity of about 200% to about 800%, measured as an increase ina weight of the nonwoven web from absorption of a liquid, a cup crushload of less than about 100 grams, when measured using a 34 gsm nonwovenweb, a bacterial filtration efficiency of about 80% or greater, or acombination thereof.
 18. The method of claim 17, wherein the adhesivecomprises an anionic component, wherein the anionic component and theadhesive are printed onto the nonwoven web.
 19. The method of claim 18,wherein the anionic component and the adhesive are flexographicallyprinted onto the nonwoven web and the plurality of staple fibers areelectrostatically adhered to the nonwoven web.
 20. The method of claim17, wherein the base sheet is calendared.